Using High-Level Petri Nets for Hierarchical Grid Workflows.

Abstract:
An increasingly popular application programming model for Grids is to
deploy often-used functionalities as remote services on high-performance
hosts, following the principles of a service-oriented architecture.
Complex applications are created by using several services and specifying
a workflow between them. We discuss how workflows of Grid applications can
be described easily as High-Level Petri Nets (HLPN), in order to
orchestrate and execute distributed applications on the Grid
automatically. In order to simplify the handling of complex and
large-scale workflows, we introduce hierarchical Grid workflows, making
use of the Petri Net refinement paradigm that allows to represent
sub-workflows by single graph elements.

We show how a complex application, the Barnes-Hut algorithm for N-Body
simulation can be expressed as a hierarchical HLPN, using our
platform-independent, XML-based Grid Workflow Description Language
(GWorkflowDL). We discuss how the GWorkflowDL can be adapted to current
Grid technologies, in particular to Java/RMI and the recent WSRF framework.